Many different types of packages to be filled with products in the form of liquid or powder are currently available.
One type of package is collapsible and comprises two side walls and a bottom wall, which walls are interconnected along a connecting portion in order to form a chamber whose volume is dependent on the relative position of the flexible walls.
Before being filled, this type of package can be in a flat and sealed state. This makes it possible to sterilize the chamber of the package at the time of manufacture and, with maintained sterility, to distribute the package to a filling plant, such as a dairy. A package of the above-described type is known from WO2005/030597.
WO 2007/091943 describes an arrangement for filling packages of the abovementioned type. Said arrangement comprises a filling tube with an end portion and a clamping element. The filling tube, which is made of a stiff material, can be inserted into a filling channel of the package for the purpose of transferring a product to the package chamber via said filling tube. The clamping element is designed to grip the end portion and the filling channel when said end portion is inserted into said filling channel, so as to create a seal between the end portion and the filling channel.
In the filling machine described above, the end portion has a peripheral surface which is principally formed by two convexly curved central portions directed away from each other, which can be likened to a boat shape. This shape is optimal for creating as large a filling area as possible given a minimal closing-together of two opposite side edges of the filling channel. The minimal closing-together of said side edges permits control of the packages during the filling operation.
To permit a reliable and reproducible insertion of the end portion of the filling tube into the filling channels of the packages that are to be filled, a predetermined minimal clearance is provided between the end portion of the filling tube and the filling channel of the package. In some applications, it is necessary for this predetermined minimal clearance to be quite large, which may be the case when the package is moved to the filling tube at great speed and/or along a nonlinear path of movement. To create a relatively large clearance of this kind, the dimensions of the filling tube can be reduced, which entails a reduced rate of flow through the filling tube, which in turn entails slower filling of the package.
The above-described arrangement for filling packages of the collapsible type can also entail a risk of leakage during the filling operation as a result of folds forming when the clamping elements grip the filling channel and the end portion of the filling tube that has been inserted into same.
There is therefore a need for a filling arrangement which permits efficient and rationalized filling of packages of the collapsible type, even when a relatively large clearance is needed between the filling channel and the inserted end portion of the filling tube, and which eliminates or in any case reduces the risk of leakage.